For the Super Bowl, FantasyPros has Rams RB Cam Akers projected at 69.4 rushing yards on 15.5 attempts. With the markets at 62.5, this suggests a bet on the over.
Not so fast my friend.
On The Football Analytics Show this week, Colin Davy, a data scientist at Facebook, talked about the importance of the distribution for player props. Here, the distribution includes the probability Akers gains zero yards, the probability that Akers gains one yard, and so on, a function that you can plot in two dimensions.
First, let’s suppose that this distribution has a familiar form. Let’s suppose it looks like a bell curve centered around a mean of 69.4 yards. Due to the symmetry of the curve, more than half of the density is greater than 62.5. This suggests a bet on Akers over his rushing yard total.
However, Colin explained that distributions for player props do not have a familiar form. And this reminded me of some work that I did on 100 yard rushers.
My hypothesis was that 100 yard rushers get to this threshold because of more carries late in the game when their team has the lead. More carries means more yards.
However, only 53.1% of yards came after halftime. This was based on 53.6% of carries after halftime. The data refuted my hypothesis.
Instead, I found that 40% of the rushing yards for 100 yard rushers came from the top two carries. Explosive plays help a running back get past the triple digit threshold.
Getting back to Super Bowl props, these explosive plays lead to a mean rushing yards higher than the median rushing yards. To see this, let’s look at a tool that Colin recommended for football: The Unabated prop calculator.
To use this tool, you enter the projected number of carries and rushing yards. The tool calculates the underlying distribution and spits out the probability of going over a yardage total.
For Cam Akers, the Unabated prop calculator gave a 53.3% chance of going over 62.5 rushing yards (in their results, they show -114 for the fair price on the over, and +114 for the under). This suggests no value on 62.5 rushing yards with a price of -115 for both the under and over.
The take home message is this: the mean projections for yards are higher than the market value. Explosive plays push the mean higher than the median. You need a tool like the Unabated prop calculator to turn projections into the right price for a market value.
At The Power Rank, I specialize in NFL spreads, and running backs have almost no impact on this market. In looking at Cam Akers props, I feel more awkward than Brian Flores at an NFL owners meeting.
Instead, let’s look at Cooper Kupp’s receiving yards. FantasyPros has a projection of 106.9 yards on 8.2 receptions. Plugging this into the Unabated prop calculator gives a 51.0% to go under 102.5 receiving yards. This suggests the slightest of values on betting under 102.5 at even money (+100), a market available at DraftKings on Thursday.
You should note how these probabilities change slowly with the yardage total. For example, Kupp has a 52.6% chance to go under 104.5 receiving yards, not that much higher than the 51.0% for under 102.5.
You need to look at the price before making a bet. You also need an account to use the Unabated prop calculator, which I highly recommend.
Football betting with a PhD edge
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